- Decades of sediment pollution, contamination and government infrastructure projects have disrupted the natural flow of saltwater and freshwater into the Ciénaga Grande of Santa Marta, one of Colombia’s key wetlands and a major estuary on the Caribbean Sea.
- Fish stocks have also plummeted, with profitable, big species being replaced by smaller ones and leaving fishing communities without their livelihoods.
- Although authorities claim that they are investing in the region, locals complain the autonomous corporation in charge is not taking steps to dredge the canals and that there isn’t enough transparency on how the money is being spent.
NUEVA VENECIA, Colombia — Sandra Milena Manjarez puts two plates of bright yellow rice topped with liza — a finger-sized mullet fish similar to a sardine — on the white plastic table on her porch. In Nueva Venecia, where homes sit on stilts in the middle of an expansive lagoon in the northern department of Magdalena, everyone subsists on fish, mainly mullet, catfish, tilapia and tarpon.
“There’s no other work here,” Manjarez told Mongabay. “What we’ve always lived on is fishing.”
The Ciénaga Grande of Santa Marta, or the “great swamp,” is a 428,000-hectare (1.06 million- acre) wetland nestled between the coastal cities of Barranquilla to the west and Santa Marta to the east. The estuary ecosystem collects water from the Caribbean Sea, the Sierra Nevada and the Magdalena River, Colombia’s largest waterway. A wildlife sanctuary, it became a Ramsar wetland of international importance in 1998 and a UNESCO Biosphere Reserve in 2000.
“[Its] hydrological configuration is difficult to find anywhere else in the word,” said Sandra Vilardy, Colombia’s former vice minister of environmental policies and standardization and an expert on the Ciénaga Grande.
“In a place where people depend on fishing, they need that input and that flow, because the Ciénaga ends up being a nursery for marine fish,” Vilardy said.
The Ciénaga estuary is home to approximately 20,000 people, part of a regional population of more than 500,000 who largely depend on the artisanal fishing economy, agriculture and livestock. The ecosystem hosts more than 200 species of birds, including migratory birds such as the blue-winged teal (Spatula discors) and native species such as cormorants (Phalacrocorax olivaceus olivaceus), anhingas (Anhinga anhinga), egrets (Ardea cocoa, Egretta alba, E. thula) plus iguanas (Iguana iguana), caimans (Crocodylus acutus) and manatees (Trichechus manatus).
But since the 1980s, decades of sediment pollution, contamination and government infrastructure projects have disrupted the natural flow of saltwater and freshwater into the region’s natural estuary, killing mangroves, reducing water quality and shrinking the fish population in both size and quantity. Despite millions of dollars in investments in the region, the local environmental agency responsible for dredging sediment and maintaining the canals that allow water to flow into the ecosystem has largely neglected its duties, experts and residents say.
The artificial canals are critical for keeping the balance between freshwater and saltwater coming into the lagoon via entrance from the Magdalena River and the Caribbean Sea. They were opened in the mid-1990s in response to issues stemming from a highway built along the coast in the late 1950s, which nearly blocked seawater flow into the Ciénaga. Another road built in the 1970s along the Magdalena River provoked the same issue with freshwater.
The area has become a “breeding ground for profound environmental deterioration,” Vilardy told Mongabay.
The canals have been poorly maintained, allowing sediment, such as sand, and aquatic plants, including water hyacinth (Eichhornia crassipes) and southern cattail (Thypha domingensis), to seep into the lagoon, clumping together to form new land and reduce the depth and amount of water available to fish.
Sedimentation “affects the quality of the water for fishing,” said Vilardy. “[It] affects the amount of oxygen and the concentration of pollution.”
Dozens of dead fish appeared floating ashore in a social media video posted by the local environmental agency in March. The fish were apparently killed by lack of oxygen and drought.
Sedimentation also “suffocates” the balance of freshwater and saltwater needed for mangrove forests, which help purify the water and air around them and provide a habitat for fish to reproduce, according to a 2023 government report.
Manjarez said she and her husband, Juan Gutierrez, catch fewer fish these days, and the ones they catch are less profitable. “Now it’s purely small fish,” Manjarez said. “You earn less.”
Her husband arrives in the evening, after 12 hours out on the lagoon looking for fish. According to him, a large fish about the size of his forearm can earn him about 10,000 Colombian pesos, or $2.50. But a fish that’s smaller than his hand, like the liza his wife cooked that day? It’s worth just 25-50 cents.
And “sometimes there’s nothing,” he added.
According to a 2023 report from the Marine and Coastal Research Institute (INVEMAR), the mullet, one of the region’s most important catches, has gone from representing about a third of total fish catch in 2021 to a tenth in 2023. The tarpon, or sábalo, a saltwater species, was nearly absent in 2023; in 2016, when more saltwater flowed into the Ciénaga, it represented one-fifth of the total catch.
The fish are also smaller, the INVEMAR report showed. Nearly 75% of mullet captured in 2023 had not reached maturity, which means they are at risk of being overfished, along with seven other key species.
Given the deteriorating environmental conditions of the Ciénaga, the government should regulate fishing activity to ensure fish populations can rebound, said Jose Ernesto Mancera, associate professor of biology at the Universidad Nacional de Colombia who has studied the Ciénaga Grande.
“The quality of water is the most important [for fish] from a biological perspective,” he told Mongabay. But “if the fishing isn’t managed … it can also deteriorate very quickly.”
No help from authorities
Two decades ago, fishers used to catch about 40 tons of fish per year, estimated Enrique Lara, a fisher who lives in Tasajera, a town on the edge of the swamp, parallel to the highway between Barranquilla and Santa Marta. Now, his colleagues average less than 10 tons per year, he said.
In November, Lara broadcast a complaint on local radio stations against Corpamag, the Magdalena Regional Autonomous Corporation, the local agency in charge of dredging sediment and repairing canals that regulate saltwater and freshwater flows into the Ciénaga.
Fishers are living “a very sad situation,” Lara said, noting they often return home empty-handed. He urged Corpamag to let local leaders observe the cleanup and provide input to their maintenance efforts. He did not receive a response, and he is planning a peaceful protest with other fishers for the end of April.
“We have no evidence [that Corpamag has done anything]”, Lara said. “It leaves us with many doubts.” Locals sometimes refer to the authority as “Corpa-nada” — “Corpa-nothing” — because their efforts to restore the Ciénaga aren’t apparent.
For example, a critical canal called Caño Clarin is “totally sedimented,” Lara said, preventing saltwater and fish from flowing in from the sea. It’s the same area where Corpamag said $1.36 million was invested in maintenance in the last four years.
Yet Corpamag’s new director, Alfredo Martinez, told Mongabay they are acting. According to Corpamag’s 2023 report, the authority invested more than $2.8 million in dredging and maintenance of the canals.
“We would like to do much more, but here there is also an issue of resources, financial resources,” Martinez told Mongabay in a video interview, noting that dredging takes many hours. According to Martinez, Corpamag has also overseen the restoration of 7 hectares (17.3 acres) of mangroves in the last four years.
But Corpamag is not subject to direct oversight from Colombia’s environmental ministry, which means there can be little visibility of how the agency spends the millions of dollars it receives, Vilardy said.
Investments with little impact
At an international level, Colombia’s government has recognized the Ciénaga Grande as “a strategic ecosystem for the conservation of global biodiversity.”
Environment Minister Susana Muhamad Gonzalez visited the region in 2023 to announce a $49 million project to restore Ciénaga Grande and improve its governance. The five-year project officially started in 2022 but didn’t get off the ground until last July.
“The objective is … to improve the health of the ecosystem of the entire Ciénaga Grande of Santa Marta,” said Carolina García, who helps oversee the project as head of information analysis in INVEMAR’s planning department.
The goal is to come up with solutions, including a new model for cooperative governance of the region, a water connectivity plan and ideas for efficient water use.
But INVEMAR will mostly focus on “high-level” research and monitoring, Garcia told Mongabay, so local residents may not immediately see the impacts. Real change requires the cooperation of other entities like Corpamag and local governments, she warned.
“We’ve always received the same complaints,” García said. “We try to help … but we must be more accompanied by other areas of the government.”
A long-term fear is that the towns of Nueva Venecia and nearby Buenavista will dry up completely, and fish will continue to disappear, said Reverend Sonia Sánchez, founder of the Fundación Derecho y Fe, a religious education NGO for kids in Nueva Venecia.
Parents drop kids off on Sánchez’s wooden porch by boat. Canoes with long poles are the primary mode of transportation in town, with no way to walk from house to house.
“The Ciénaga is life, it is the lungs,” Sanchez said, not just for people but for hundreds of species who call it home. “It purifies, and inside its mangroves, there are infinite fish and birds.”
Sánchez holds up a water hyacinth and water drips from its roots. It’s one of hundreds covering the water outside the foundation’s community house, clumping on top of the water’s surface to form new pieces of land.
“[Corpamag has] to dredge,” she said. “Five years ago, they [did]. They haven’t returned.”
Dredging is the most simplistic solution, said Vilardy, but the real issue is restoring the natural hydrological flows into the Ciénaga estuary. Complete restoration requires coordination from Corpamag, local governments and nongovernmental organizations that work in the area.
For Sánchez, it’s hard to understand how groups that “handle euros [and] dollars” don’t have enough money to clear sediment, repair canals and address locals’ concerns.
Since 2021, an INVEMAR-supported effort to bring tourists to the stilt villages has provided an economic boost, and groups of visitors weave through the Ciénaga’s lakes a few times a week. But tourism is only as sustainable as the community itself.
Back in Nueva Venecia, Manjarez serves a dinner of arepas and hard-boiled eggs at night. There are no more fish to cook that day.
The village is dark except for a few house lights, and the stars and moon reflect on the water.
“What happens when you live on fish, [it determines] how you can cook or not cook,” Manjarez said.
“We’ve adapted,” she said. “With everything that’s happened here, we’ve remained.”
Banner image: Nueva Venecia is one of three “floating” stilt villages perched on the water in the Ciénaga Grande, or “Great Swamp,” between the Caribbean cities of Barranquilla and Santa Marta. Image by Austin Landis for Mongabay.
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